Continually variable transmission

ABSTRACT

The invention relates to a transmission which is continually variable from an input shaft (E) to an output shaft (S), in which the input power is divided and transmitted along two parallel paths, namely a fixed ratio path and a variable ratio path, the respective speeds thereof being combined at an epicyclic output gear ( 7 ). The variable ratio path is formed by an epicyclic gear ( 5 ), a pulley variator ( 1, 2, 3 ) and an epicyclic gear ( 6 ) having two different ratios with which the brake ( 6.3 ) or coupling ( 6.5 ) is actuated. Two speed ranges (L and H) are provided at the output shaft (S). The L range passes from negative speeds to positive speeds, through a neutral point, when the variator ratio is reduced. The H range provides increasing positive speeds when the course of the variator is reversed. The passage between ranges L and H is synchronised at the point at which the speed of the intermediate shaft ( 5.3 - 6.5 ) is cancelled. The invention, which dispenses with the need for the standard reverse gear and clutch, can be used to obtain a wide variety of speeds for the output shaft (S).

OBJECT OF THE INVENTION

The present invention refers to a continually variable transmission, of the type of transmission of movements using variable speed device, one of each has a conical surface.

This invention is characterised by its special construction of a transmission with power derivation at the output and to the main motor, incorporating an intercalated differential mechanism which reduces the rotation speed of the intermediate shaft to zero in either direction, thus achieving the advantages of a greater speed variation range, using the high torque transmitted, apart from the financial savings deriving therefrom.

BACKGROUND TO THE INVENTION

For some years mechanical power systems have been known of the type able to continually change their rate of speed, generally in the range of medium and low power, usually obtained by continual variation of the ratio of the radiuses of two pulleys, in particular in those applications in which their characteristics lend themselves to this type of system, such as agricultural machinery and also the “gear box” of all kinds of vehicles.

Another related registration is patent no. U.S. Pat. No. 6,517,461 in the name of Nissan Motor Co., which consists of a transmission mechanism incorporating a helical gear which meshes with a final outlet gear which transmits rotation to the final mechanism of the shaft, with the sides of the teeth and the final outlet the final output shaft of a ring gear arranged in such a way that the force exercised on the ring by a planetary gear and the force exercised by the transmission act in opposite directions.

In the automotive field patent ES 2068047 may also be cited:. “Continual mechanical gear change” which incorporates a pair of tapered pulleys, with an intermediate flexible transmission element together with a power transmission mechanism and a planetary gear arranged at the outlet connecting, the first pulley to the entry shaft of the system, while the second is connected to the entry shaft of the power transmission mechanism, the outlet shaft of which activates one of the planetary elements while the remaining elements are related respectively with the entry shaft and the outlet shaft of the device which is the object of the invention, in various arrangements and distributions of these elements.

Despite its validity and opportunity, this invention generates a discontinuity in the transmission relation between the pair of pulleys, in particular with respect to the shaft speed of the entry and outlet shafts, which leads to a need to change the direction of the outlet shaft when the speed is still relatively high, with subsequent disadvantages in the long term with respect to stress and wear etc.

The applicant is unaware of mechanical transmissions which are genuinely continual and with a high range of variation of revolutions of the outlet shaft, in addition to high torque, which resolve the aforementioned problem by incorporating a differential mechanism which dispenses with the need for reverse gear and clutch, and which also resolves this problem with the simplicity and effectiveness of the invention described herein.

DESCRIPTION OF THE INVENTION

The present invention refers to a continually variable transmission, of the type of transmission of movements using variable speed device and in particular, one of these having a conical surface as well as incorporating epicyclic gears.

An external driving couples to the aforementioned variable speed device, partially receiving power from the motor shaft by means of a pinion gear and provided with tapered pulleys both of which connected to a differential mechanism, for example, one of these connected to the crown wheel of an epicyclical gear, while the other pulley is linked to the sun and the satellite carrier of the planetary gear set and transmits that power to a subsequently arranged reducer mechanism.

This reducer, for example, may be a new epicyclical gear which is arranged intermediately in respect of another outlet device in a similar construction.

The reducer of the sun is coupled to the satellite carrier of the differential mechanism. A device which blocks the sun and the satellite carriers of the reducer in this phase permits a transmission ratio of 1:1. Optionally, the satellite carrier may be blocked with the crown wheel obtaining the same effect.

The satellite carrier of the reducer is provided with a means of fixation as a brake so that having established this fixation, the group acts as a reducer. The crown wheel is connected to the sun of the final reduction phase.

In this outlet device or final phase of reduction, identified as third epicyclical gear the satellite carrier is in turn connected to the outlet shaft of the transmission, in this way deriving the aforementioned fraction of the entry power to the two pulleys. It will be seen that in an example of an embodiment the crown wheel of this third epicyclical gear is coupled to the entry shaft.

In order to reduce the speed of the outlet shaft of the final epicyclical gear in any of its directions to zero, to this transmission construction described with, on one hand, derivation of power to the outlet and, on the other, to the main drive body, it is required that the pulley connected to the motor shaft is arranged as closely as possible to the maximum diameter and that the sun and the differential satellite carrier are interlocked.

The fact that there are no relative speeds between the coupling bodies enables the clutches such as those used in the state of the art to be dispensed with when they are designed to absorb different relative speeds.

In the forward gear, in order to increase the outlet variation range the fact that the differential outlet speed is zero when the motor pulley approximates to the range of minimum diameter is taken advantage of to stop the epicyclical gear satellite carrier with the interlocking mechanism at zero speed of the intermediate shaft, that is, with without friction. In this way a different transmission ratio is applied which enables the motor pulley to be varied in the opposite direction however, continually increasing the speed of the mechanism outlet.

In addition, in order to obtain reverse movement the pulley attached to the motor shaft should be positioned at its maximum diameter with the satellite carrier interlock disconnected and with the sun joined to the satellite carrier.

To summarise, this means of working with continual speed variation is as follows:

Rotation at the outlet of the final Diameter of Sun-satellite Satellite epicyclical the power carrier carrier gear pulley interlock Interlock Reverse Maximum Connected Disconnected Stopped Close to Connected Disconnected maximum Forward Reducing Connected Disconnected Forward rapid Close to Connected Disconnected and close to minimum intermediate range Intermediate Minimum Disconnected Connected range (outlet speed of the differential shaft = 0 Increasing Increasing to Disconnected Connected speed to the the maximum maximum

DESCRIPTION OF THE DRAWINGS

The present descriptive report is complemented by a set of plans illustrating a preferred embodiment of the invention but which is in no way restrictive.

FIG. 1 shows a diagram of the transmission according to a preferred embodiment of the three interconnected epicyclical gears of the invention.

PREFERRED EMBODIMENT OF THE INVENTION

The present invention refers to a continually variable transmission, of the type of transmission means using variable speed device and in particular, one of these having a conical surface as well as incorporating epicyclical gears.

In accordance with the preferred embodiment of FIG. 1, an external drive (1) is coupled to the variable speed device (2) and (3) connected to an epicyclical gear (5) partially receiving the power from the motor shaft, by means of a gear pinion(4) and with the tapered pulley (2) connected to the crown wheel (5.1) through transmission means (10) and (11) in this example, of the epicyclic gear (5) while the other pulley (3) is linked to the sun (5.2) and the satellite carrier (5.3) transmits this power to a subsequently arranged epicyclic gear (6) coupled or interlocked (6.5) with the satellite carrier (6.2) of the epicyclic gear (6), in addition the satellite carrier (6.2) is coupled to an interlock (6.3) and its crown wheel (6.4) is connected to the sun (7.1) of the epicyclic gear (7) the satellite carrier of which (7.2) is in turn connected to the outlet shaft (8) of the transmission, thus deriving from this the aforementioned fraction of the entry power to the two pulleys (2) and (3) while the crown wheel (7.3) of this third epicyclical gear (7) is made with the gear pinion (9) of the entry shaft.

In order to reduce the speed of the outlet shaft (8) of the epicyclic gear (7) to zero in any direction it is essential that the pulley (3) connected to the motor shaft is arranged close to the maximum diameter and that the sun (6.1) and the satellite carrier (6.2) of the epicyclic gear (6) are interlocked.

In order to obtain reverse gear, the pulley (3) should be positioned at its maximum diameter, with the interlocking (6.3) of the satellite carrier (6.2) disconnected and connecting the interlock (6.5).

In the forward gear, a progression of pulley (3) diameters is made from the diameter closest to maximum to the diameter closest to minimum and with the interlocking (6.3) of the satellite carrier (6.2) disconnected and connected to the interlock (6.5). In order to increase the outlet variation range, the fact that the satellite carrier (5.3) outlet speed is zero when the pulley (3) approximates to its range of minimum diameter is taken advantage of to stop the epicyclical gear satellite carrier (6.2) with the interlocking mechanism (6.3) at zero speed of the intermediate shaft.

In order to further increase the range of actuation the pulley (3) progression is varied in the inverse direction, that is, from its minimum diameter to its maximum diameter.

The aforementioned mechanical transmission effectively generates a continual reduction, either a continual multiplication or a continual transmission ratio of 1:1.

In applications with low torque requirement and/or reduced variation range, the epicyclical gear(6) may be dispensed with, thus joining the satellite carrier (5.3) of the epicyclical gear (5) with the sun (7.1) of the epicyclical gear (7).

The essential nature of this invention is not altered by any variations in materials, form, size and arrangement of its component elements, described in a non-restrictive manner, with this being sufficient to proceed to its reproduction by an expert. 

1. Continual mechanical transmission of the type of transmission using variable speed device and in particular one of these having a conical surface and incorporating at least one epicyclical gear, characterised by a special construction of a transmission with power derivation to the outlet and to the main drive body, incorporating an intercalated differential mechanism which reduces the rotation speed of the intermediate shaft to zero in either direction, thus achieving continual transmission formed by the following elements, a drive, variable speed device, a differential mechanism, a reducer and an epicyclical gear so that the external drive is coupled to variable speed device, partially receiving the power from the motor shaft and provided with pulleys connected to the differential mechanism which transmits that power to the subsequently arranged reducer mechanism, so that the differential receives the two outlets presented by the continual variator, thus following the differential an outlet is obtained combining the two speeds with the reducer placed intermediately with respect to the other device so that by means of various fixation combinations of the constituent elements of the reducer, different transmission ratios are obtained which, together with the combination of pulley diameters, provide various outlet speeds to the differential shaft, with finally, an epicyclical mechanism whose final outlet shaft speed varies in any direction, reverse, forward, stopped, by means of a combination of different diameters of the drive pulley, together with various forms of interlocking of the reducer elements generating either a continual reduction, or a continual multiplication or a continual transmission ratio.
 2. Mechanical continual transmission according to the previous claim characterised in that the external drive (1) is coupled to the variable speed device (2) and (3) connected to an epicyclical gear (5), partially receiving the power from the motor shaft, by means of a gear pinion(4) and with the tapered pulley (2) connected to the crown wheel (5.1) of an epicyclical gear (5) through transmission means (10) and (11), while the other pulley (3) is linked to the sun (5.2) and the satellite carrier (5.3) transmits this power to a subsequently arranged epicyclical gear (6) intermediate with respect to the other similar epicyclical gear (7) with the sun (6.1)of the epicyclical gear (6) coupled or interlocked (6.5) with the satellite carrier (6.2) of the epicyclical gear (6), in addition to which the satellite carrier (6.2) is coupled to an interlock (6.3) and its crown wheel (6.4) is connected to the sun (7.1) of the epicyclical gear (7) the satellite carrier (7.2) which is in turn connected to the outlet shaft (8) of the transmission, thus deriving from this the afore-mentioned fraction of the entry power to the two pulleys (2) and (3) while the crown wheel (7.3) of this third epicyclical gear (7) is made with the gear pinion (9) of the entry shaft.
 3. Mechanical continual transmission according to previous claims, characterised in that in order to reduce the speed of the outlet shaft (8) of the epicyclical gear (7) to zero in any direction it is essential that the pulley (3) connected to the motor shaft is arranged close to the maximum diameter and that the sun (6.1) and the satellite carrier (6.2) of the epicyclical gear (6) are interlocked.
 4. Mechanical continual transmission according to the previous claims characterised in that in order to obtain reverse gear, the pulley(3) should be positioned at its maximum diameter, with the interlocking (6.3) of the satellite carrier (6.2) disconnected and connecting the interlock (6.5).
 5. Continual mechanical transmission according to the previous claims, characterised in that the forward gear makes a progression of pulley (3) diameters close to the maximum up to the diameter closest to minimum, and with interlock (6.3) of the satellite carrier (6.2) disconnected and with the interlock (6.5) connected, and in order to increase the outlet variation range, the fact that the differential outlet speed is zero when the pulley (3) approximates to the minimum diameter range is taken advantage of to stop the epicyclical gear satellite carrier (6.2), with the interlocking mechanism at zero speed of the intermediate shaft, and to increase the range of actuation, the progression of the pulley (3) in the opposite direction is varied, that is, from its minimum diameter to its maximum diameter.
 6. Continual mechanical transmission according to the previous claims, characterised in that in applications with low torque requirement and/or reduced variation range, the epicyclical gear(6) may be dispensed with, thus joining the satellite carrier (5.3) of the epicyclical gear (5) with the sun (7.1) of the epicyclical gear (7). 